Field
Various communication systems may benefit from techniques for handling inter-band carrier aggregation (CA). For example, systems of the third generation partnership project (3GPP) long term evolution (LTE) advanced (LTE-A) may benefit from inter-band TDD CA with different UL-DL configurations on different bands. Furthermore, it is beneficial to provide a uplink (UL) downlink (DL) configuration zero handling, particularly in cases where there is no physical hybrid automatic repeat request (HARQ) indicator channel (PHICH). For example, certain embodiments may be applicable to inter-band CA having different UL/DL configuration in use.
Description of the Related Art
In LTE release 10 (Rel-10), up to five component carriers with same time division duplex uplink/downlink (UL/DL) configurations can be supported in carrier aggregation. In LTE Rel-11, inter-band time division duplex carrier aggregation with different time division duplex uplink/downlink configurations on different bands may further enhance carrier aggregation.
Inter-band carrier aggregation of time division duplex component carriers (CCs) with different uplink/downlink configurations include characteristics such as co-existence with the neighboring legacy time division duplex system; support of aggregation of traffic-dependent carriers in heterogeneous networks; flexible configuration, for example, more uplink subframes in lower frequency band for better coverage and more downlink subframes in high frequency band for traffic transmission; and higher peak data rate.